Field
The present invention is directed in general to wireless communication systems. In one aspect, the present invention relates to a method and system for transferring data at different rates over wireless communication protocol.
Description of the Related Art
Wireless communication devices used to form a wireless personal area network (WPAN) often have limited power sources and signaling infrastructure. These design limitations present significant challenges in terms of data transfer capabilities and power consumption during operation for extended periods of time. Consequently, various protocols have been developed to implement WPANs using small, power-efficient, inexpensive communication devices. For example, IEEE Standard 802.15.4 is a standard which specifies the physical layer and medium access control for low-data-rate, low-power wireless personal area networks in which very low cost wireless communications to nearby devices are provided with little to no underlying infrastructure and limited power consumption.
IEEE 802.15.4 defines a standard for Wireless Personal Area Networks (WPAN) including 2.4 GHz Offset-Quadrature Phase Shift Keying (O-QPSK) Direct Sequence Spread Spectrum (DSSS) devices with a physical (PHY) layer mode that provides a bit rate of 250 kbps and a packet payload of up to 127 bytes. This bitrate and payload can be limiting when using advanced wireless protocol stacks, such as 802.15.4e, however. From a network perspective, two main limitations of the legacy IEEE 802.15.4 PHY devices are (1) low throughput at the PHY layer, which translates into low throughput at NWK layer, and (2) small PHY service data unit (PSDU) size, which requires fragmentation at the upper layers. Advanced PHY modes for stack layers offer advantages including higher throughput, eliminating or reducing packet fragmentation, and creating dedicated links in the network topology for more efficient routing while maintaining backward compatibility with legacy versions of the 802.15.4 standards. Accordingly, it is desirable to provide a wireless communication protocol that enables advanced devices to take advantage of faster data rates and larger frame sizes while still allowing legacy devices to operate in the same network.